docs: def save(self):
          """ Save the UFO."""
  
          # handle glyphs that were muted
          for name in self.mutedGlyphsNames:
              if name not in self.font: continue
              if self.logger:
                  self.logger.info("removing muted glyph %s", name)
              del self.font[name]
              # XXX housekeeping:
              # remove glyph from groups / kerning as well?
              # remove components referencing this glyph?
  
          # fontTools.ufoLib no longer calls os.makedirs for us if the
          # parent directories of the Font we are saving do not exist.
          # We want to keep backward compatibility with the previous
          # MutatorMath behavior, so we create the instance' parent
          # directories if they do not exist. We assume that the users
          # knows what they are doing...
          directory = os.path.dirname(os.path.normpath(self.path))
          if directory and not os.path.exists(directory):
              os.makedirs(directory)
          try:
              self.font.save(os.path.abspath(self.path), self.ufoVersion)
          except defcon.DefconError as error:
              if self.logger:
                  self.logger.exception("Error generating.")
              return False, error.report
          return True, None